Utility of routine use of breast ultrasound following contrast-enhanced spectral mammography.

AIM: To evaluate whether breast ultrasound (US) is routinely indicated following contrast-enhanced spectral mammography (CESM). MATERIALS AND METHODS: Consecutive screening and diagnostic CESM examinations with concurrent breast US were collected retrospectively (May 2012 to February 2016). Radiologists assigned a separate Breast Imaging-Reporting and Data System (BIRADS) score for CESM and for US. BIRADS scores were grouped into three categories: normal/benign appearing (BIRADS 1, 2); probably benign, short-term follow-up (BIRADS 3); or suspicious appearing (BIRADS 0, 4, 5). Patients with a suspicious-appearing lesion in either US or CESM underwent biopsy. The associations between malignant pathology with either suspicious-appearing CESM or suspicious-appearing US were calculated. The sensitivities and specificities of CESM and US were analysed. RESULTS: Eighty-seven lesions were biopsied, 37 (43%) biopsies were malignant and 50 (57%) were benign. Although suspicious-appearing CESM was associated with malignant biopsies (p<0.0001), suspicious-appearing US was not (p=0.985). Among 37 malignant biopsies, CESM had a sensitivity of 97% (36/37 lesions), compared to 92% (34/37 lesions) with US. None of the malignant biopsies were normal/benign appearing with CESM. One case of follow-up CESM was suspicious-appearing at US and proved to be malignant on biopsy. The specificity of CESM was 40%, which was significantly higher than US at 8%. CONCLUSION: When CESM is suspicious appearing, subsequent US and biopsy is appropriate. With a CESM BIRADS 3, correlation with US is suggested. If the CESM is benign appearing, the routine use of US is questionable, as it may lead to unnecessary benign biopsies.

Challenges in contrast-enhanced spectral mammography interpretation: artefacts lexicon.

AIM: To review and describe commonly encountered artefacts in contrast-enhanced spectral mammography (CESM). MATERIALS & METHODS: This retrospective study included 200 women who underwent CESM examinations for screening and diagnostic purposes. Analysis was performed on the image data sets of these women, comprising of a total of 774 subtracted images. Images were reviewed with focus on the presence of four artefacts: rim ("breast within breast"), ripple (black and white lines), axillary line, and skin-line enhancement (skin-line highlighting). Statistical cross-correlation and association with acquisition parameters (tube current, tube voltage, compression force, breast thickness, paddle size) was compared using Fisher's exact test and t-test. RESULTS: The rim artefact was highly common (97-99%) in every projection. The ripple artefact was increasingly more common on the oblique projections (80-82%) and found to be associated with higher breast thickness values. The axillary line artefact was detected only on oblique projections (63%) and associated with the use of a small compression paddle. The skin-line enhancement artefact was seen in 19-46% of projections. None of the artefacts interfered with image interpretation. CONCLUSIONS: Two main artefacts commonly seen on CESM are rim and ripple artefacts. They do not hamper with image interpretation. It is important to be aware of them and prevent misinterpretation of these artefacts as real breast pathology.